Saturday, 24 December 2016

Those tyres: 650b x 42

A couple of weeks ago I posted my review of my Cannondale Slate. And, like more or less everyone who's reviewed the Slate, I said nasty things about the slick tyres. What's wrong with the tyres?

Well, on tarmac, they're excellent. They're fast rolling and supple, which, on tarmac, adds up to excellent grip. The problem is that the Slate isn't designed just for tarmac, and I don't use mine just for tarmac. It's a bike for roads, paths, tracks and trails. On damp grass, damp rocks, mud, or more or less any other off road surface in the wet west of Scotland, the degree of grip available is sketchy at best. To be fair, dropping the pressure does help a little bit.

Stopping at each junction between tarmac and non-tarmac to deflate or inflate the tyres would be stupid and impractical and I've no plans to do it, but they'll run at 3.1bar/45psi on tarmac without and significant deterioration of performance, and this is a compromise which more or less works. For now.

But I've been looking for a replacement 650b x 42 tyre with a bit of tread, particularly on the shoulders, because sooner or later those tyres are going to let go unexpectedly and I'm going to go down hard. I'm a little old to enjoy that, now. And the truth is there really isn't much available.

Schwalbe have two options, the Marathon Supreme which is semi-slick and, as Schwalbe themselves say, has poor offroad grip; and the G1 (actually in 40mm width, but that will fit), which has a fine overall tread which would probably roll well on road but I imagine would clog rapidly in mud. Their Hurricane, which might be the sort of profile I'm looking for, isn't available in 650b at less than 50mm wide.

Panaracer offer their Gravelking tyre in 650b x 1.5", which is more or less the same fit. It has a very slight tread - very slight indeed. They also do a Col de la Vie touring tyre, which has a diamond tread pattern which might work.

There are some minor American brands offering 650b x 42. There's a thing called a Grand Bois Hetre, which has barely perceptible tread; I don't think it would work in Scottish conditions. There's a thing called a Babyshoe Pass, which has just a tiny bit more. Mind you, it claims to be designed for mountain conditions in Washington State, which I don't imagine are very dry. And finally in this group there's the Soma Cazadero, which has decidedly more bite and would definitely be better off road - but probably less good on road.

All these boutique American tyres are very expensive - the Cazadero comes in at US$73.99 per tyre, before you've paid shipping.

The thing which most closely resembles what I think I want is the Continental Tour Ride, which Continental describe as an 'urban tyre'; it has a smooth central tread and chunky shoulder blocks. However, it's discontinued and I cannot find that its replacement, the Ride Tour, is available in 650b. Also, although Continental are a German company, I cannot find any European retailer offering the 650b version of this tyre.

And that's all I can come up with. It's not a big range.

There are good technical reasons for choosing the 650b x 42 tyre size: it produces a higher volume tyre, able to cope with rougher surfaces, with the same outside diameter as a 700c x 23, and consequently with race bike geometry. But if companies like Cannondale want to sell bikes with 650b wheels, they're going to have to persuade more tyre manufacturers to support them.